Hi Consuehlo,

No your guide was not pulling your leg! Although the specimen you saw was only small I believe that it is a tree that grows to 35 metres called Dendrocnide Moroides. There is also Dendrocnide Excelsa. I'm not sure of the differences between them. Some common names are gympie gympie (aboriginal form gimpi gimpi) and stinging tree.
I have no reference to the 'guardian' name.

It grows in the rainforest in clearings or along tracks where the sunlight has a chance to penetrate the canopy.

Fine hairs on heart shaped leaves penetrate the skin even if brushed against lightly. It can cause excruiciating pain, headaches and even illness which can need medical treatment. I haven't heard of the suicide cases, but who knows?

I hope this helps. I'm sure that with an identification now, you will be able to google up more information than I have supplied.

Cheers,
Dee.

Hi Consuehlo,

There are indeed several species of stinging tree, all belonging to the genus Dendrocnide, which contains about 70 species of which 4 are found in the warmer rainforests of Queensland and NSW. All seem to grow at the rainforest's edge and are species that characterise varying stages of regrowth. They are members of the family Urticace, the same family as the stinging nettles, and for some years the trees were called Tree Nettles (not to be confused with the nettle trees Celtis spp.).

They operate by having leaves with 'hairs' made of hollow tubes of silica. These contain varying concentrations of formic acid (the same acid used by many stinging ants and wasps). When contact is made with the leaves the hairs penetrate skin and break off, delivering syringe-like injections of the acid. The pain caused varies from species to species. In general, the furrier the leaf the more stings and the worse effects of the venom.

The least painful is the Shiny-leaved Stinging Tree D. photinophylla. Sometimes it appears not to have any effect at all. I believe there is still such a plant remaining as a street tree in the NSW town of Forster. Few people realisie what it is and so it has been allowed to stay there and is quite an attractive small tree. I mentioned this many years ago to a group of teenagers as I passed through the town. They found themselves drawn magnetically to the tree and couldn't stand not to try it out. Despite warnings they touched it, apparently to no effect. Soon half a dozen of them were wiping leaves over their arms and legs, showing how game they were. Remarking that it was all rubbish, they went off. Half an hour later the effects seem to kick in and they all complained of a an intensely annoying and rather painful, stinging itchiness like a sharp, irritating rash that took an hour or two to wear off.

The largest and second most painful is the Giant Stinger D. excelsa, a buttressed rainforest giant growing to 40 metres (over 120 feet in imperial). It has leaves the size of dinner plates and is definitley not something to trifle with. Its sting is intensely painful and can endure for hours. In sensitive people it can last for much longer and recur on humid days when the hairs still remaining in the skin wash a little more poison in. I have often heard (hopefully) aprocryphal stories about this common tree such as the one about the female German entomologist who was collecting insects in North Queensland and needed to urinate. Still wearing her gloves she is said to have found a plentiful supply of large soft leaves from a nearby tree and used them as toilet paper. If she wasn't hospitalised afterwards she should have been for even thinking about it.

The third and definitely nastiest is the spreading bush called the Gympie Gympie D. moroides. As the Giant Stinger is to the Shiny-leaved Stinger so it is in turn to the Giant. Its equally large, rounded leaves cause a far more intense, painful and...

Dee and rodaf, the information you've volunteered is truly fascinating! I've been wondering about this plant for about a decade now in the back of my head (7th grade students are quite impressionable to such horror stories). Thank you so much for your help; I'm looking forward to writing the last science paper of my college career. =)

You will find a lot of information on the web page linked below.

I have personally sampled the stings of both Dendrocnide excelsa and D. moroides, and can also attest to D. photinophylla being relatively benign.

One time when I was collecting a botanical specimen of D. moroides in North Queensland I was accidentally stung on the hand, a very slight contact with a very small area of skin. The immediate pain was bad enough, but what was noteworthy was the pain in my armpit lymph nodes 10-15 minutes later. This went away before very long, but the sting itself was painful and tingling for maybe the next day (this was 20 years ago so I can't be too precise). What I noticed in the following weeks or maybe even months was that the site of stinging on the back of my hand was sensitive to any touch, which would produce an unpleasant tingling sensation, rather like a old wound. Another time I was wearing sandals and, walking off the road edge, was stung on the foot by a 3-inch high seedling of D. moroides -- very painfully!

I also understood that the toxic substance in the stinging hairs is nothing so simple as just formic acid, though that may be present. This is supported in the internet article already referred to.

Here is a link that might be useful: Article on Dendrocnide

Thank God, D. moroides is rare in NSW!!!!
Kris

Kris,

I was stung by D. moroides on a walk up to Running Creek falls in southern Lamington National Park. It happened to be the first D. moroides I had come across in S.E Qld, I just had to walk into it didn't I! Unfortunately besides taking great care I was also stung by D. excelsa and D. photinophylla on the same day! I was re-living the event for a number of weeks afterwards evertime I had a shower.

Andrew.

A Nth Qld Publication on rainforests also stated the Gympie Gympie was used as a true "guardian of the rainforest" by planting them in sensitive areas to protect the endangered plants from being stolen.
Note. The term "Guardian Of the Rainforest" was not used in the book however the purpose was clearly stated.

Doug.